The present invention relates generally to ball bearings and more particularly to ball bearings for linear motion.
There are in the prior art many forms of ball bearings for linear motion such as those disclosed in U.S. Pat. Nos. 3,545,826 and 3,900,233. The present invention relates to new and useful improvements over the aforesaid patents and to new and useful improvements in ball bearings for linear motion. In many instances where ball bearings for linear motion are used in combination with a shaft, the loads may be applied from any radial direction so that it is desirable for the individual ball circuits to be relatively evenly spaced within the bearing sleeve and around the shaft.
However, there are instances such as certain machine tool uses where the loads are not evenly applied and it is not necessary for the ball circuits to be evenly spaced around the shaft. In certain machine tools, for example, the primary deflection loads are in one or two specific directions with less deflection loads in other directions. In such an environment, the conventional ball bearing for linear movement may not be constructed in such a way as to adequately handle the primary loads. Particularly in the case of an "open" type bearing used in combination with a shaft supported along its length, the primary radial loads are normally applied either toward or away from the open side of the bearing. In other words, the loads are applied either towards the closed portion or the open portion of the bearing which are separated by 180.degree..
Another problem encountered in linear ball bearing involves the accurate alignment of the ball circuits of the retainer with the ball grooves of the races without involving excessive manufacturing costs. This problem can be acute where several circumferentially spaced circuits of balls are contained within a single large retainer element. It has proven to be difficult to accurately match the circumferential spacing of these retainer circuits with the circumferential spacing of the groove of the mating bearing plates resulting in misalignment and wear and tear on the bearing assembly.
There is a need, therefore, for a ball bearing for linear motion where the load carrying balls are spatially located so as to support more concentrated loads applied in specific directions. There is also a need for a ball bearing structure wherein misalignment between the ball guiding tracks of the retainers and the ball grooves in their associated bearing plates is substantially eliminated.
In view of the foregoing, it is an object of this invention to provide a new and improved ball bearing for linear motion.
Another object of this invention is to provide a new and improved ball bearing for linear motion having improved load bearing characteristics.
A further object of this invention is to provide a new and improved ball bearing for linear motion which is particularly adapted for use where the heaviest loads are applied in specific directions.
Still another object of this invention is to provide a new and improved ball bearing for linear motion which is particularly adapted for use in applications where heaviest loads are applied in specific directions in that the ball circuits are circumferentially positioned so as to maximize the capacity of the bearing when the loads are applied in the specific directions.
A further object of this invention is to provide a new and improved ball bearing for linear motion wherein the balls within each retainer circuit can be quickly, expeditiously and accurately assembled in alignment with respect to the ball grooves in its mating bearing plate, and will automatically maintain that proper alignment during operation.
Additional objects and advantages of the invention will be set forth in the specification which follows and, in part, will be obvious from the description, the objects and advantages being realized and obtained by means of the parts, instrumentations, methods, apparatus and procedures particularly pointed out in the appended claims.